filter/tex/lib.php

   1 <?php  //$Id$
   2
   3 function tex_filter_get_executable($debug=false) {
   4     global $CFG;
   5
   6     $error_message1 = "Your system is not configured to run mimeTeX. You need to download the appropriate<br />"
   7                      ."executable for you ".PHP_OS." platform from <a href=\"http://moodle.org/download/mimetex/\">"
   8                      ."http://moodle.org/download/mimetex/</a>, or obtain the C source<br /> "
   9                      ."from <a href=\"http://www.forkosh.com/mimetex.zip\">"
  10                      ."http://www.forkosh.com/mimetex.zip</a>, compile it and "
  11                      ."put the executable into your<br /> moodle/filter/tex/ directory.";
  12
  13     $error_message2 = "Custom mimetex is not executable!<br /><br />";
  14
  15     if ((PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows")) {
  16         return "$CFG->dirroot/filter/tex/mimetex.exe";
  17     }
  18
  19     $custom_commandpath = "$CFG->dirroot/filter/tex/mimetex";
  20     if (file_exists($custom_commandpath)) {
  21         if (is_executable($custom_commandpath)) {
  22             return $custom_commandpath;
  23         } else {
  24             error($error_message2.$error_message1);
  25         }
  26     }
  27
  28     switch (PHP_OS) {
  29         case "Linux":   return "$CFG->dirroot/filter/tex/mimetex.linux";
  30         case "Darwin":  return "$CFG->dirroot/filter/tex/mimetex.darwin";
  31         case "FreeBSD": return "$CFG->dirroot/filter/tex/mimetex.freebsd";
  32     }
  33
  34     error($error_message1);
  35 }
  36
  37 function tex_sanitize_formula($texexp) {
  38     /// Check $texexp against blacklist (whitelisting could be more complete but also harder to maintain)
  39     $tex_blacklist = array(
  40         'include','command','loop','repeat','open','toks','output',
  41         'input','catcode','name','^^',
  42         '\def','\edef','\gdef','\xdef',
  43         '\every','\errhelp','\errorstopmode','\scrollmode','\nonstopmode',
  44         '\batchmode','\read','\write','csname','\newhelp','\uppercase',
  45         '\lowercase','\relax','\aftergroup',
  46         '\afterassignment','\expandafter','\noexpand','\special',
  47         '\let', '\futurelet','\else','\fi','\chardef','\makeatletter','\afterground',
  48         '\noexpand','\line','\mathcode','\item','\section','\mbox','\declarerobustcommand'
  49     );
  50
  51     return  str_ireplace($tex_blacklist, 'forbiddenkeyword', $texexp);
  52 }
  53
  54 function tex_filter_get_cmd($pathname, $texexp) {
  55     $texexp = tex_sanitize_formula($texexp);
  56     $texexp = escapeshellarg($texexp);
  57     $executable = tex_filter_get_executable(false);
  58
  59     if ((PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows")) {
  60         $executable = str_replace(' ', '^ ', $executable);
  61         return "$executable ++ -e  \"$pathname\" -- $texexp";
  62
  63     } else {
  64         return "\"$executable\" -e \"$pathname\" -- $texexp";
  65     }
  66 }
  67
  68 /**
  69  * Purge all caches when settings changed.
  70  */
  71 function filter_tex_updatedcallback($name) {
  72     global $CFG;
  73     reset_text_filters_cache();
  74
  75     if (file_exists("$CFG->dataroot/filter/tex")) {
  76         remove_dir("$CFG->dataroot/filter/tex");
  77     }
  78     if (file_exists("$CFG->dataroot/filter/algebra")) {
  79         remove_dir("$CFG->dataroot/filter/algebra");
  80     }
  81     if (file_exists("$CFG->dataroot/temp/latex")) {
  82         remove_dir("$CFG->dataroot/temp/latex");
  83     }
  84
  85     delete_records('cache_filters', 'filter', 'tex');
  86     delete_records('cache_filters', 'filter', 'algebra');
  87 }
  88
  89 ?>